Configure Tomcat’s Resource Factory

Tomcat 7, Oracle 11g

<Resource name="jdbc/dsName" auth="Container">
maxActive="100"
maxIdle="10"
removeAbandoned="true"
removeAbandonedTimeout="1200"
testWhileIdle="true"
testOnBorrow="true"
validationQuery="select 1 from dual"
poolPreparedStatements="false"/>

Note: Read this article and pick up required attributes based on project.
http://tomcat.apache.org/tomcat-7.0-doc/jndi-resources-howto.html